1. Field of the Present Description
The present invention relates in general to the field of repairing structural components.
2. Description of Related Art
Structural components often are damaged during manufacture or while in service. If damage to a structural component affects the structural integrity of the component or undesirably affects the ability for loads to be transmitted between the structural component and other structural components, the structural component is replaced or repaired. Replacement is sometimes cost prohibitive and/or is very difficult to accomplish. For example, the tooling required to replicate a part may no longer exist. In some circumstances, therefore, repair is highly desirable over replacement. It is very important that the repair made to the structural component result in a repaired component that exhibits mechanical properties (e.g., tensile strength, stiffness, etc.) that are at least comparable to the original, unrepaired, undamaged structural component.
Proper repair is particularly important when addressing damage in airframe components. Improper repair may directly lead to a failure of an airframe component and, in extreme cases, loss of the aircraft. Moreover, it is highly desirable for repairs to airframe components to be a weight efficient as possible, so that the payload of the aircraft is not adversely affected.
FIG. 1 depicts a structural component 101 exhibiting various exemplary types of damage that may be incurred during manufacture and/or in service. Note that, for each of the defect examples exhibited by structural component 101, the desired configuration of structural component 101 is shown in phantom. For example, structural component 101 may define an elongated fastener hole 103 or 105, rather than substantially round fastener holes 107 and 109, respectively. Elongated fastener holes 103, 105 are positioned substantially correctly with respect to other features of structural component 101 but are not shaped appropriately. Elongated fastener holes 103, 105 may be produced by inferior drilling processes during manufacture. Alternatively, proper, round fastener holes 107, 109 may become elongated (i.e., become elongated fastener holes 103, 105, respectively) while in service as a result of structural component 101 moving with respect to fasteners (not shown) extending through round fastener holes 107, 109.
Moreover, during manufacture, a fastener hole 111 that is larger in diameter than a desired fastener hole 113 may be drilled or otherwise generated in structural component 101. If structural component 101 is attached to another structural component (not shown) by a fastener (also not shown) extending through enlarged fastener hole 111, structural component 101 may not be sufficiently affixed to the other structural component, thus allowing structural component 101 to move with respect to the fastener or with respect to the other structural component. Furthermore, a desired fastener hole 115 may actually be produced in structural component 101 at an undesired location, as fastener hole 117, thus preventing structural component 101 from being attached to other structural components. In some situations two (or more) overlapping holes 118a and 118b may be generated in structural component 101. Whether either of holes 118a and 118b is in a desirable location, having overlapping holes is not acceptable. This undesirable configuration is often referred to as a “double-drilled” hole.
Corners and other edges of structural component 101 may also be damaged during manufacture or while in service. For example, a corner portion 119 and/or an edge portion 121 of structural component 101 may be broken off, worn away, or otherwise undesirably removed from structural component 101, leaving structural component 101 with improper edges 123, 125, respectively. In particular, structural component 101 may be trimmed or cut incorrectly, producing edges 123 and/or 125. Structural component 101 may not perform as designed because portion 119 or 121 is missing.
One way of repairing damaged structural components is to add additional structural components, often known as “doublers,” to reinforce the damaged structural component. For example, as shown in FIG. 2, a first doubler 201 and a second doubler 203 are added to structural component 101 so that a properly-sized fastener hole 205 can be provided for attaching structural component 101 to another structural component. The addition of such doublers, however, changes the effective thickness of structural component 101 to include the thicknesses of doublers 201 and 203. In assemblies wherein thickness of structural component 101 is important, such as in assemblies that include interchangeable and/or replaceable structural components, the use of doublers may not be possible.
Moreover, such conventional repair techniques may be difficult to accomplish in the field. Field repairs require techniques that can be accomplished without significant equipment or special environments.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.